Prove theorems about lines and angles. Theorems include: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; points on a perpendicular bisector of a line segment are exactly those equidistant from the segment's endpoints.

Pair-Share for Angle Relationship Vocabulary

Practice with Scaffolded Proofs

15 minutes

Using student notes on page 6, students can cut out the key pieces of a practice proof. Students can work in pairs or small groups to arrange the proof and then glue or paste the correct order of the proof onto page 8 of notes. You may want to consider how this proof could be created as a paragraph proof, rather than a 2-column proof before asking students to cut the pieces of the proof up (MP #7).

Please note that page 7 has been left blank for students to cut out the pieces of their proof.

You can review the steps with students, and discuss how these are connected to prior topics covered in geometry (i.e. sums of angles and reflexive property) (MP #3).

Student Notes - Prove It with Angle Relationships.doc

Proofs_Proving It Angles_p 6-8.pdf

Activity/Homework

10 minutes

Students will work on activity attached to student notes and continue this as a homework assignment, if time is short in class.